What Makes Them Click: Empirical Analysis of Consumer Demand for Search Advertising
利用微软Live的用户数据，研究用户对搜索广告的点击行为，发现广告竞争减少点击量，优化广告匹配和个体定向能显著提升福利。
We study users' responses to sponsored-search advertising using consumer-level data from Microsoft Live. We document that users click ads in a nonsequential order and that the clickthrough rates depend on the identity of competing ads. We estimate a dynamic model of utility-maximizing users that rationalizes these two facts and find that 51 percent more clicks would occur if ads faced no competition. We demonstrate that optimal matching of advertisements to positions raises welfare by 27 percent, and that individual-level targeting raises welfare by 69 percent. Revealing the quality of the advertiser prior to clicking on a sponsored link raises welfare by 1.6 percent.